After much deliberation, I have decided to install a $300 Chipwerke Pro piggyback tuner in my 2015 Q5 TDI. As one who has never done any modifications to a car, even this little step was big for me. Here's why.

My 2011 Touareg is/was the best car I've owned. (It's parked awaiting the buyback.) Amazing car, amazing engine! The only problems were recurring issues with the emissions control system, which required replacement of various components, all but $200 of which was covered under warranty or comped due to the 2nd failure of a covered part. When dieselgate came to light, some unsavory disclosures came with it. Of course, VW had cheated the regulators — not good — but at first it seemed maybe they had done it to deliver a better product to the customer. But then came the revelation that VW knew their emissions system was likely to fail under the expected workload, and that the cheat was motivated by a desire to delay these failures until after the standard warranty had expired, leaving the customer holding the bill.

Yet when the buyback was announced, I found I couldn't do without the amazing torque and efficiency of the 3.0 TDI engine. I decided on a Q5, and found my current car with under 10K miles on the clock.

Although I am anticipating that CARB and the EPA will approve a fix for the 3.0 gen 2 engines (MYs 2013-2016), I think it is likely that the fix will do one or both of the following: 1) degrade the engine's performance and economy; 2) put more stress on the emissions system. This is a concern, obviously. I don't really want to give up any performance at all if I can avoid it, and I'd just as soon do without a number of trips to the dealer to replace overstressed components. On the plus side, however, these vehicles will be covered by a long extended warranty of not only the emissions system but the HPFP and engine itself. I don't want to lose the extended warranty — it was a key feature in deciding to double down on a TDI, and absolutely essential to VW's having an opportunity to earn back my trust. So I am not going to take any steps (emissions delete, ECU tune) that would run the risk of voiding that warranty.

With a little encouragement and advice from TDI club member BarryT82, I came to see the Chipwerke piggyback tuner as a way to possibly have my cake and eat it too. I can insure myself against possible degradations in vehicle performance, while at the same time preserve my extended warranty coverage, since the Chipwerke is removable and therefore undetectable by diagnostic software. Furthermore, Chipwerke's website claims that the tuner can not only deliver power gains but also increase fuel efficiency via more mpg's. This attracts me, also. I have posted a few monster tanks so far with the "new" Q5. I live in the country, no stoplights, essentially the perfect scenario for great mileage. I don't obsess about it, but I'd be lying if I said I don't smile when I calculate a tank of 35. But what if I could get 38? So, I'm curious.

Chipwerke makes tuners for both gassers and diesels. In diesels, it works by adjusting pressure in the common rail. Here is a link to a page of their website explaining the idea:

Bought it on eBay last week and installed it today in about 10 minutes. You disconnect the rail pressure sensor connector under the engine cover and attach the Chipwerke harness in its place, then you connect the original connector to the other end of the harness. The module has a 15 pin connector of its own that attaches to the harness as well. You hang the module in a relatively cool, dry place in your engine bay, away from other electronics.

Who knows, maybe it will do nothing, and this will be a short thread explaining how I returned the module for my refund. But I'm more optimistic. Anyway, what I plan to do is report back soon with some feedback. It may take a while for me to form some definite conclusions. But I'll probably have some initial observations to report within a week. In the meantime, I invite others, especially Barry, to join me in sharing observations and/or data on this thread. With the current state of affairs in 3.0 TDI land, we might just have a very workable solution.

* noticeable improvement in power in two situations
--power doesn't flag above 4000 rpm but continues to swell up towards red line
--at low rpm's, car less dependent on downshifting but can much more hold a given gear even under acceleration

For the first phase, I wanted to drive as much as possible like I was before, meaning same style, use paddle shifters mode, etc. even same fuel. Next I want to get data on MPG. After that, drive much more under automatic transmission and get idea of how well and smoothly it shifts in a variety of conditions. (I have driven a little bit in automatic mode and not noticed any bad or jerky shifting so far.)

As for MPG, more in my future posts, but the early evidence suggests that it will increase with Chipwerke compared to without.

With respect: If you do a search for Chipwerke you'll find that whenever someone asks or tells about their product the thread tends to get clogged with claims for competing products, downplaying, and IPhone vs. Android type arguments. I'd like to avoid some of that by pointing out that I am not in the market for a true tune, probably not until 2024 when the extended warranty runs out, and I am trying to share observations with others whose position is like mine. I don't have a dyno handy, but I know how to calculate mpg's and I feel I can contribute some reasonably objective observations along with some common sense.

Here is my update for today. If the powers that be will reopen the other thread, they can copy this post to it. I too would like to continue the conversation. I've seen this type of thread get derailed and clogged on other occasions.

I just completed another long drive today, around 300 miles. There is little doubt the piggyback tuner has enabled me to hold taller gears. My mpg (display, not yet calculated, because not finished) for the first post Chipwerke tank is at 39.2, which is 5-10% higher than normal for the type of driving I do. I'll post more soon. I'm not giving up on this thread.

My supposition is that the increased rail pressure may be putting more stress on emissions components, in the form of temperature or another factor. On the other hand, I am currently under warranty, and will be under some form of engine/emissions warranty until the fall of 2024. Otherwise, I have yet to encounter any downside to it.

I don't claim that a Chipwerke or any kind of piggyback system would or should be compared to a true ECU tune. Under the current warranty, though, it may be a sensible choice, and it is very low cost at $300.

Here is my update for today. If the powers that be will reopen the other thread, they can copy this post to it. I too would like to continue the conversation. I've seen this type of thread get derailed and clogged on other occasions.

I just completed another long drive today, around 300 miles. There is little doubt the piggyback tuner has enabled me to hold taller gears. My mpg (display, not yet calculated, because not finished) for the first post Chipwerke tank is at 39.2, which is 5-10% higher than normal for the type of driving I do. I'll post more soon. I'm not giving up on this thread.

My supposition is that the increased rail pressure may be putting more stress on emissions components, in the form of temperature or another factor. On the other hand, I am currently under warranty, and will be under some form of engine/emissions warranty until the fall of 2024. Otherwise, I have yet to encounter any downside to it.

I don't claim that a Chipwerke or any kind of piggyback system would or should be compared to a true ECU tune. Under the current warranty, though, it may be a sensible choice, and it is very low cost at $300.

Haha, yeah, I went on a nice drive yesterday, but took the old Touareg cause it hadn't been out in a while. As soon as I get the Q5 tank refilled, I'll calculate and share the number. Thanks for your patience!

Haha, yeah, I went on a nice drive yesterday, but took the old Touareg cause it hadn't been out in a while. As soon as I get the Q5 tank refilled, I'll calculate and share the number. Thanks for your patience!

I really love the interior fit and finish of the 14 Q5 we bought in february, and it's returned 31 ish MPG in the 2K miles we have driven it. We satarted driving an 11 Exec and and it's only returning 25 MPG so far. I love the look and room of the Touareg, but man O man, what a slug compared to the Q5.

Wife took the car out today. Good news is we'll refill sooner and have a number sooner. Bad news is it won't be as high because she can't drive without running up on the car in front of her and then hitting the brakes, haha. Good news is if the number is higher than before we'll know there really is a fuel savings. Bad news is we won't know how much. Good news...

First full tank of diesel under Chipwerke came back at 35.2, which is fine, not a huge deal though. The average of three fills previously was 34.6. Another couple of fill ups would help me see if there is a trend. Sorry it is taking so long to accumulate data. The darn range on this thing is huge. I went 591 miles on that tank and could have gone another 100.

I suspect when I average a few tanks I will have experienced a 5-10% increase in mpg. It's just hard to measure because it's a shared car and my driving characteristics differ so much from my wife's, haha.

As for power, I am more aware of an improvement when I drive in manual mode. This is something I am able to do all the time since I have the sport package (paddle shifters). In full auto I can't tell as much. (The tranny under auto shifts too readily, in my opinion. The Q5 TDI has 8 gears. I can easily go 2-4-6 when controlling them myself.)

(Disclaimer: you will likely not get 35+ mpg. I drove 210 miles today, average speed of 45 mph, and encountered five stop lights. That is typical for me, probably not typical for you, heh.)